Felt Bobs and Lubricants
Polishing felt bobs and abrasive lubricants for metallographic finishing. Our felt bobs are made from high-quality wool in soft, medium, and hard densities, supplied mounted or unmounted; our lubricants come in water-, oil-, and alcohol-based formulations (pint, quart, and gallon) matched to our diamond compounds, suspensions, and sprays. Used to extend abrasive and cloth life and control the polishing action across metallography, ceramics, optics, and tool-and-die finishing.
Felt Bobs — Density and Mounting
Felt bobs carry charged diamond or oxide abrasive for polishing and finishing, and reach shaped or contoured surfaces that a flat cloth on a platen cannot. Density controls how the bob conforms and holds form: soft felt conforms to contours and is gentler on the surface; hard felt holds its form and edge definition for flat faces and defined features; medium is the general-purpose density. Mounted bobs come on a spindle or shank for a rotary handpiece or flexible-shaft tool; unmounted bobs fit your own arbor.
Choosing a Lubricant Base
The lubricant (also called an extender) cools the surface, carries away swarf, keeps the abrasive cutting instead of drying on the cloth, and controls cut rate. Match the base to the abrasive carrier and the material:
| Base | Best For | Notes |
|---|---|---|
| Water-based | General polishing and rapid cleanup. | Pair with water-soluble abrasives; avoid on water-reactive metals. |
| Oil-based | Reactive or moisture-sensitive materials; longer working time. | Pair with oil-soluble abrasives; less evaporation on long cycles. |
| Alcohol-based | Fast drying and moisture-sensitive specimens. | Additional cooling in a non-aqueous carrier; evaporates quickly. |
Lubricants are supplied in pint, quart, and gallon. Match the base to the carrier of your diamond compound, suspension, or spray so the two do not separate on the cloth.
Frequently Asked Questions
What are felt bobs used for?
Felt bobs polish and finish with charged abrasive, especially on shaped or contoured surfaces that a flat platen cloth cannot reach. Choose soft felt for a gentler, conforming action, hard felt to hold form and edge definition, and medium for general use. Bobs are supplied mounted (on a spindle) or unmounted to fit your own arbor.
Which lubricant base should I choose?
Use water-based for general work and quick cleanup, oil-based for reactive or moisture-sensitive materials and longer working time, and alcohol-based for fast drying and extra cooling. Match the base to your abrasive's carrier — water-soluble diamond with a water base, oil-soluble diamond with an oil base — so the abrasive stays suspended and cutting.
Why use a lubricant at all?
The lubricant cools the surface, flushes swarf, and keeps the abrasive from drying on the cloth or bob, which maintains cut rate and extends both abrasive and cloth life. Dosing depends on the step and system: apply enough to keep the surface wet and the abrasive moving without flooding away the diamond.
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